Squeak DBX

1. Smalltalk
Programmer
Ing. Mariano Martínez Peck marianopeck@gmail.com

2. SqueakDBX
The complete and G
IN to
E T
open-source solution
Kdatabase
A R
relational
M access

3. SqueakDBX team
Mariano Germán
Hernán
Cassinelli
M. Peck Esteban Lorenzano Palacios

4. F.A.Q
Who are we?
How did it begin?
What is actually SqueakDBX?

5. RDBMS VS. OODB
Please, don't fight ;)

6. Anyway, we rather program in
objects and use RDBMS than
using Java with RDBMS
;)

7. Survey 1/2
How many times were you forced to use a
particular database?

8. Survey 2/2
Which databases?

9. Squeak's current situation
Only MySQL and PostgreSQL native
drivers.
Limited ODBC driver
Glorp in Squeak
only works with
PostgreSQL

10. We are in trouble...
Direct SQL queries: 20%
Using GLORP: 8.52%

11. Our goal
Direct SQL queries: 100%
Using GLORP: 100%

12. Our purpose

13. OpenDBX architecture
Oracle uses oci.h and and libmysqlclient_r.
MySQL uses mysql.h libclntsh.
It has N functions.
M functions. Common API
for all backends!!!
Examples: OCIHandleAlloc(), OCIServerAttach(),
mysql_real_connect(), mysql_server_end(),
OCISessionEnd(), etc.
mysql_real_query(), etc.
Oracle MySQL PosgreSQL Sqlite SQLServer
client client client client client
library library library library library

14. Why OpenDBX?
It is fast
Simple to use
Flexible
Cross platform
Asynchronous queries
Specific RDBMS features
Good documentation

15. Deployment and infrastructure
PC1 PC2
Squeak image
Database
OpenDBX
Database
Client Library

16. Smalltalk and C
Squeak image
|
OpenDBX
#include <stdio.h>
#include <stdio.h>
static int mysql_odbx_get_option( odbx_t*)
static int mysql_odbx_get_option( odbx_t*)
switch( option )
switch( option )
.....
.....

17. Smalltalk-C Connector
FFI (Foreign Function Interface)
Main problem: Locks the entire VM

18. Squeak ODBC driver queries
VM locked
time

19. OpenDBX Connector
FFI (Foreign Function Interface)
Main problem: Locks the entire VM
Our solution:
✔ Asynchronous queries
✔ “Mini” VM locks
✔ Retry schema
✔ DBXQuerySettings>>timeout:

20. SqueakDBX queries
VM locked
time

21. Database access in Smalltalk
SqueakDBX Smalltalk driver
✔ One for all databases ✗ One for each database
✔ Less time and effort ✗ More time and effort
✔ Good performace ✗ Performance issues?
✔ OSS and proprietary ✗ Only OSS
✗ Difficult to debug ✔ Easier to debug
✗ Platform dependent ✔ Platform independent
✗ FFI locks the VM ✔ Non-locking

22. SqueakDBX design
SqueakDBX Structure (API)
SqueakDBX Structure (API)
SqueakDBX Platform
SqueakDBX Platform
OpenDBX Connector
OpenDBX Connector
{
{
DBXConnection
DBXConnectionSettings
DBXResultSet
DBXPlatform
DBXResult
DBXSpecialOptions
DBXRow
DBXErrorSeverity
...
DBXTimeSpec
...
FFI
FFI SqueakDBXPlugin
SqueakDBXPlugin
OpenDBX

23. Showtime

24. Who can use SqueakDBX?
An application
Glorp
Magritte-RDB
SqueakSave
Moe

25. Current backends and OS

26. Benchmark for PostgreSQL
1800
1600
1400
1200
1000
ms
800 SqueakDBX
Native
600
400
200
0
Converted Insert Select1000
Insert Select100
tests

27. Benchmark for MySQL
700
600
500
400
ms
300 SqueakDBX
Native
200
100
0
Converted Insert Select1000
Insert Select100
tests

28. Features
Mini VM locks
SqueakDBXPlugin
Automatic fields conversion
Configurable logging/trace
Special RDBMS features
Multistatements
Automatic release of resources

29. What do we have?
Enough unit tests
Acceptable test coverage
SmallLint runs
Good enough design
GLORP integration

30. Documentation
Website
Documented code
Mailing list
Benchmarks

31. What will come
Complete Glorp refactor and integration
More backends in more OS
Large objects support
Better SPs and functions support
Continue with SqueakDBXPlugin
Try Alien FFI
Port to Smalltalk/X ?

32. Glorp progress
Port from Squeak to Pharo
First refactor to SqueakDatabaseAccesor
Driver for native driver
Driver for SqueakDBX (PostgreSQL)

33. Glorp before SqueakDBX

34. Glorp after SqueakDBX

35. Special thanks to...
Norbert Sendetzky
GLORP Alan Knight
Stéphane Ducasse

36. aConnection execute: 'select * from questions
where has_answer = true'
Ing. Mariano Martínez Peck marianopeck@gmail.com

37. Thank you
very much